Left Main Coronary Artery Segment Research Articles

Lipid-rich large plaques in a non-culprit left main coronary artery and long-term clinical outcomes.

An integrated backscatter (IB) intravascular ultrasound (IVUS) provides an information about tissue components and vulnerability of coronary plaques. The presence of vulnerable plaque in non-culprit lesion is associated with future clinical events. The purpose of this study was to assess the association between the characteristics of non-culprit left main coronary artery (LMCA) plaques evaluated by IB-IVUS and long-term clinical outcomes in patients undergoing percutaneous coronary intervention (PCI). Among the patients who underwent non-LMCA PCI, we studied 366 patients with adequate LMCA IVUS images. Conventional and IB-IVUS analyses of the LMCA segment were performed. Lipid-rich large plaque was defined as the presence of both a lager plaque volume and a higher percentage of the lipid component than the obtained median values. Major adverse cardiovascular events (MACE) included cardiac death, myocardial infarction, and unplanned revascularization. The mean age of the patients was 68.5±10.2years, 79.8% were men. Median follow-up period was 6.0years (IQR: 4.2-8.1years). The incidence of MACE was significantly higher in patients with lipid-rich large plaques (P=.006). The incidence rates of cardiac death, myocardial infarction, and unplanned revascularization were significantly higher in patients with lipid-rich large plaques (P=.02, 0.004, and 0.02, respectively). Multivariate Cox regression analysis showed that the presence of a lipid-rich large plaque was significantly associated with MACE (HR: 1.74; 95%CI: 1.17-2.58; P=.006). The presence of lipid-rich large plaques in a non-culprit LMCA can be associated with the long-term MACE in patients who have undergone PCI.

Left main coronary artery disease: pathophysiology, diagnosis, and treatment.

The advent of coronary angiography in the 1960s allowed for the risk stratification of patients with stable angina. Patients with unprotected left main coronary artery disease have an increased risk of death related to the large amount of myocardium supplied by this vessel. Although coronary angiography remains the preferred imaging modality for the evaluation of left main coronary artery stenosis, this technique has important limitations. Angiograms of the left main coronary artery segment can be difficult to interpret, and almost one-third of patients can be misclassified when fractional flow reserve is used as the reference. In patients with clinically significant unprotected left main coronary artery disease, surgical revascularization was shown to improve survival compared with medical therapy and has been regarded as the treatment of choice for unprotected left main coronary artery disease. Two large-scale clinical trials published in 2016 support the usefulness of catheter-based revascularization in selected patients with unprotected left main coronary artery disease. In this Review, we describe the pathophysiology of unprotected left main coronary artery disease, discuss diagnostic approaches in light of new noninvasive and invasive imaging techniques, and detail risk stratification models to aid the Heart Team in the decision-making process for determining the best revascularization strategy for these patients.

Coronary Plaque Morphology and the Anti-Inflammatory Impact of Atorvastatin: A Multicenter 18F-Fluorodeoxyglucose Positron Emission Tomographic/Computed Tomographic Study.

Nonobstructive coronary plaques manifesting high-risk morphology (HRM) associate with an increased risk of adverse clinical cardiovascular events. We sought to test the hypothesis that statins have a greater anti-inflammatory effect within coronary plaques containing HRM. In this prospective multicenter study, 55 subjects with or at high risk for atherosclerosis underwent 18F-fluorodeoxyglucose positron emission tomographic/computed tomographic imaging at baseline and after 12 weeks of treatment with atorvastatin. Coronary arterial inflammation (18F-fluorodeoxyglucose uptake, expressed as target-to-background ratio) was assessed in the left main coronary artery (LMCA). While blinded to the PET findings, contrast-enhanced computed tomographic angiography was performed to characterize the presence of HRM (defined as noncalcified or partially calcified plaques) in the LMCA. Arterial inflammation (target-to-background ratio) was higher in LMCA segments with HRM than those without HRM (mean±SEM: 1.95±0.43 versus 1.67±0.32 for LMCA with versus without HRM, respectively; P=0.04). Moreover, atorvastatin treatment for 12 weeks reduced target-to-background ratio more in LMCA segments with HRM than those without HRM (12 week-baseline Δtarget-to-background ratio [95% confidence interval]: -0.18 [-0.35 to -0.004] versus 0.09 [-0.06 to 0.26]; P=0.02). Furthermore, this relationship between coronary plaque morphology and change in LMCA inflammatory activity remained significant after adjusting for baseline low-density lipoprotein and statin dose (β=-0.27; P=0.038). In this first study to evaluate the impact of statins on coronary inflammation, we observed that the anti-inflammatory impact of statins is substantially greater within coronary plaques that contain HRM features. These findings suggest an additional mechanism by which statins disproportionately benefit individuals with more advanced atherosclerotic disease. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00703261.

Left main coronary arterial endothelial function and heterogenous segmental epicardial vasomotor reactivity in vivo: novel insights with intravascular ultrasonography.

While the relationship between epicardial coronary vasomotor reactivity and cardiovascular events is well established, this observation has yet to be evaluated within the left main coronary artery (LMCA) in humans in vivo. Our aims were to test the endothelium-dependent vasomotor properties of the LMCA, and to compare these responses to downstream epicardial segments. Thirty patients referred for coronary angiography underwent intracoronary (IC) salbutamol provocation during intravascular ultrasound imaging within a non-critically diseased, left-sided conduit vessel. Macrovascular vasomotor response [change in average lumen area (LA) at baseline and following 5 min of 0.30 µg/min IC salbutamol] and percent atheroma volume (PAV) were evaluated in 30 LMCA, 42 proximal, 109 mid, and 132 distal epicardial coronary segments. In comparison with all other segments, the LMCA had the greatest lumen and vessel areas (P < 0.001), yet the proximal epicardial segments contained the greatest PAV (P < 0.02). The mid and distal epicardial segments displayed significant endothelium-dependent vasodilatation from baseline (P = 0.017 and <0.001, respectively); however, the proximal epicardial and LMCA segments did not (P = 0.45 and 0.16, respectively). Significant segmental vasomotor heterogeneity was noted in all 30 patients, with opposing vasomotor responses between adjacent LMCA and epicardial segments. Across all segments, baseline LA inversely correlated with the % change in LA (r = -0.16, P = 0.0005). Endothelium-dependent vasomotor reactivity is heterogenous within the conduit coronary system. Vascular dynamic responses were less prominent in the larger calibre LMCA and proximal epicardial segments. This may, in part, relate to higher shear stress in smaller, distal segments and yet also may explain the propensity for culprit plaques to cluster proximally.

Comparison of two and three dimensional quantitative coronary angiography to intravascular ultrasound in the assessment of left main coronary artery bifurcation lesions

Background Angiographic evaluation of left main coronary artery (LMCA) bifurcation lesions is often limited. two dimensional (2D) quantitative coronary angiography (QCA) with segmental analysis provides accuracy for quantification of the degree of stenosis in the main vessel and side branch ostium but can be affected by foreshortening and variable magnification. The accuracy of three dimensional (3D) QCA has recently developed to overcome 2D QCA limitations, however, accuracy and precision of 3D bifurcation QCA measurements in LMCA bifurcation lesions has not been established. Methods We investigated whether such 3D and 2D bifurcation QCA measurements differ in their accuracy in assessing significant LMCA bifurcation lesions defined by intravascular ultrasound (IVUS) as a minimum luminal area (MLA) &lt;6 mm2 of LMCA and MLA &lt;4 mm2 of proximal left anterior descending (LAD) and/or proximal left circumflex (LCX) Results LMCA bifurcation lesions were assessed in 44 patients undergoing elective percutaneous coronary intervention. From 2D QCA measurements, MLA correlated moderately with threshold intravascular ultrasound MLA for LMCA (r=0.81, P &lt;0.000 1), LAD (r=0.54, P=0.000 1) and LCX (r=0.58, P &lt;0.000 1). Severity of lesion as MLA by derived 3D QCA, correlated moderately with threshold intravascular ultrasound MLA for LMCA (r=0.84, P &lt;0.000 1), LAD (r=0.53, P=0.000 2); LCX (r=0.66, P &lt;0.000 1). Overall, the C statistics tended to be slightly higher for 3D QCA and 2D QCA measurements in LMCA segment compared with proximal LAD and LCX segments, and there were no significant predictive power of percent diameter stenosis and percent area stenosis on 3D QCA for LCX IVUS MLA &lt;4 mm2 (percent diameter stenosis: area under curve 0.55, cutoff 23%, sensitivity 88%, specificity 37%, P=0.618 6; percent arer stenosis: area under curve 0.56, cutoff 41%, sensitivity 83%, specificity 38%, P=0.518 4, respectively). Conclusions The accuracy of 3D bifurcation QCA in detecting significant LMCA bifurcation lesions is limited, especially the proximal LCX ostium. When IVUS is not available or contraindicated, 3D QCA may assist in the evaluation of intermediate LMCA lesions with MLA.

Left Main Coronary Atherosclerosis Progression, Constrictive Remodeling, and Clinical Events

The aim of this study was to evaluate the progression of atherosclerosis within the left main coronary artery (LMCA) in association with risk factor modifying therapies. Despite studies demonstrating slowing of disease progression within epicardial coronaries with risk factor modification, little is known about the natural history and clinical sequelae of atherosclerosis progression within the LMCA. In 340 patients with angiographic coronary artery disease who underwent serial intravascular ultrasound imaging to evaluate the effects of anti atherosclerotic therapies across 7 clinical trials, LMCA and epicardial disease progression was characterized. Relationships between changes in plaque burden with remodeling parameters and the incidence of major adverse cardiovascular events (MACE) (death, myocardial infarction, hospital stay for unstable angina, and coronary revascularization) were investigated. Plaque regression was observed in the LMCA segment, and progression was observed in adjacent epicardial segments (percent atheroma volume [PAV] -0.39 ± 0.1% vs. +0.37 ± 0.1%, p < 0.001). Changes in LMCA lumen volume correlated strongly with changes in external elastic membrane (beta coefficient 0.91, p < 0.001) and negatively with the change in PAV (beta coefficient -0.55, p < 0.001). Patients who experienced a MACE had smaller baseline LMCA minimum lumen area (11.6 vs. 12.2 mm(2), p = 0.05) and greater progression of PAV in the LMCA (+0.51 ± 0.3% vs. -0.35 ± 0.2%, p = 0.02) compared with those who were MACE-free. Significant reductions from baseline in both external elastic membrane (-4.7 ± 1.7 mm(3), p < 0.01) and lumen volumes (-4.0 ± 1 mm(3), p < 0.01) were also observed in those having an event. Left main coronary atherosclerosis responds to systemic risk factor modification. Patients experiencing a MACE were more likely to demonstrate progressive disease and constrictive arterial remodeling within the LMCA segment.

Cardio-Ankle Vascular Index Could Reflect Plaque Burden in the Coronary Artery

Cardio-ankle vascular index (CAVI) using the volume plethysmographic method is a noninvasive atherosclerotic indicator which is not influenced by blood pressure. Coronary intravascular ultrasound (IVUS) is a reliable technique to measure progression of atherosclerosis. The association between CAVI and IVUS has not been reported. The aim of this study was to evaluate the association between CAVI and the plaque burden measured by IVUS in the left main coronary artery (LMCA) in patients with coronary heart disease and normal LMCA. Cardio-ankle vascular index was significantly correlated with percentage plaque area (r = .649, P < .0001) measured by IVUS in the most diseased segment of LMCA. Cardio-ankle vascular index remained significant among cardiovascular disease risk factors included in the multiple regression analysis predicting percentage plaque area. Cardio-ankle vascular index was a good atherosclerotic indicator and associated with the plaque burden in nonculprit and angiographically normal LMCA.

Bail‐out stenting for left main coronary artery dissection during catheter‐based procedure: Acute and long‐term results

The optimal treatment of patients with left main coronary artery (LMCA) dissection during catheter-based procedure remains uncertain. In cases with significant LMCA dissection occurring during catheter-based procedure, prompt stent implantation may be safe and associated with favorable clinical outcome. We evaluated the acute and long-term results of bail-out stenting for LMCA dissection occurring during a catheter-based procedure in 10 patients. Initially, there was no significant stenosis of LMCA segments in these patients. Catheter-induced dissection occurred in eight patients (during diagnostic angiography in three patients and during guiding catheter manipulation in five patients). Two patients suffered dissection in the setting of stent deployment in other vessels. Therefore, bail-out stenting for LMCA dissection was performed in a total of 10 patients. In four patients, hypotension developed and an intra-aortic balloon pump was placed during the procedure. Stents were successfully deployed in all patients; there was no in-hospital mortality. Six-month angiographic follow-up was performed in eight patients. No angiographic restenosis (diameter stenosis > or = 50%) was observed in any patient at follow-up study. During a mean follow-up of 31 +/- 25 months after hospital discharge, there was no major adverse cardiac event (death, myocardial infarction, and target lesion revascularization). Bail-out LMCA stenting is technically feasible and showed good acute and long-term results in a small series of patients.

Intravascular ultrasound evidence of angiographically undetected left main coronary artery disease and associated trauma during interventional procedures.

To determine the clinical significance of angiographically undetected left main coronary artery (LMCA) disease, we analyzed data from 47 patients, with a mean age of 58 years, who were examined with intravascular ultrasound (3.5 Fr, 30 MHz). For assessment of atherosclerosis, the lesion area was calculated from the ultrasound images of the formula, [(total vessel area--lumen area)/total vessel areas] x 100(%). In 37 LMCA segments of patients with significant distal coronary stenosis (> 50%), the percent intima-media area (the index) was 39 +/- 11% (mean +/- SD), significantly greater than that of 10 patients without distal disease (27 +/- 4%, P < 0.01). Among those with significant coronary stenosis, the index was markedly greater in patients with multi-vessel coronary stenosis (46 +/- 12%, n = 19) than in patients with single-vessel disease (33 +/- 9%, n = 18; P < 0.01). At three LMCA sites associated with multi-vessel disease, ultrasound analysis demonstrated disruption of the intima at the site where the guiding catheter for balloon angioplasty had been positioned. These results indicate that LMCA disease is more prominent in patients with multi-vessel distal coronary disease than in those with single vessel disease, even in the absence of angiographic stenosis. We suggest that LMCA trauma can occur where the guiding catheter for angioplasty is positioned, particularly in patients with multi-vessel distal disease.

Left main coronary artery stenosis: angiographic determination.

Reliability of angiographic assessment of the left main coronary artery segment was evaluated by review of 106 coronary cineangiograms from the Coronary Artery Surgery Study. The films were interpreted by three groups of angiographers: those at a clinical site, those at a quality control site, and those on a study census panel. Among the readings of these three groups, there was 41% to 59% agreement on the severity of the lesion, with 80% agreement on whether the lesion was greater or less than 50%. The severity of lesion, its location, or presence of ectasia or calcium did not affect the discrepancy rate, whereas segments that were unusually short, diffusely diseased, or obscured by overlapping vessels were especially difficult to interpret.

Regional coronary angiographic observations during cold stimulation in patients with exertional chest pain: Comparison of diameter responses in normal and fixed stenotic vessels

In 12 patients with exertional chest pain, coronary angiography was periormed and quantitative measurements of coronary artery (CA) diameters were made before and during cold stimulation (four normal CA patients and eight fixed CA stenosis patients). The left main CA; proximal, middie and distal anterior descending and circumflex segments; and small intramyocardial CAs (0.4 to 1.0 mm) usually showed only minimal and similar degree of vasoconstriction (average diameter reduction 6%) during cold stimulation in both normals and CA disease (CAD) patients. Magnitude of vasoconstriction differed among some CA segments measured; the left main CA segment (0 ± 2%, mean ± SD) usually did not change while distal segments (−10 ± 10%) usually demonstrated greatest percentage vasoconstriction. Coronary stenoses and CAs filled by collaterais did not demonstrate increased magnitude of vasoconstriction compared to other CAs. Results of other CA segments were also similar comparing patients with and without CAD. The minimal degree of vasoconstriction observed in these CA segments does not appear to account for the large increase in coronary resistance reported during cold stimulation in CAD patients.